Abrasive cut-off machine



July 30, 1935. H. G. ROBINSON 2,009,859

ABRASIVE CUT-OFF MACHINE Filed June so, 1931 4 Sheets-Shet '1 elm v y 1935- H. G. ROBINSON 2,009,859

ABRA SIVE CUT-OFF MACHINE Filed June 30, 1931 4 Sheets-Sheet 2 'July 30, 1935. ROBINSON 2,009,859

ABRASIVE CUT-OFF MACHINE Filed June 30, 1931 4 Sheets-Sheet 5 .mmmw

H w H July 30, 1935.

H. G. ROBINSON ABRASIVE CUT-OFF MACHINE Filed June 30, 1931 4 Sheets-Sheet 4 Patented July; 30, 1955 Q Q UNITED STATES PATENT. OFFICE ABRASIVE CUT-OFF MACHINE Harry G. Robinson, Waterbury, Conn., assignor, by mesne assignments, to American Chain Company, Incorporated, Bridgeport, Conn., a corporation of New York Application June 30, 1931, Serial No. 547,811

8 Claims. (01. 51-438) This invention relates. to an abrasive cut on also showing e preferred form of W Clamp machine, and has for an object to provide a more in front elevation; improved machine for cutting off stock .of various Fig. '7 is a vertical section substantially on th materials which it is difficult to cut off by ordiline 1-1 of'Fig. 6; nary methods. Fig. 8 is a transverse section substantially on 5 It is also an object of the invention to provide the line 8-8 of Fig. 6; a machine which will cut this material much Fig. 9 is a top plan view showing the preferred more rapidly and at less cost than can be done form of work holding means; with machines now generally employed. Fig. 10 is a side elevation thereof; 10 It is another object of the invention to provide Figs. 11 and 12 are a top plan view and side 10 an improved construction for this type of maelevationof the modified form of work clamp; chine to facilitate convenience in easy operation Figs. 13 and 14 are a top plan view and end eleof the machine, and which will give a strong and vation of one of the work supporting locks;

rigid construction so that the work will be ac- Figs. 15 and 16 are top plan view and side eleva- 15 curately cut and thin abrasive cut off wheels tion respectively of another modified form of 15 running at high speed can be used. work support; and

Another object of the invention is to provide Figs. 17 and 18 are side and edge elevations an improved means for mounting the abrasive respectively of the cut off abrasive wheel or disc wheel so that it may be moved toward and from which can be used in this machine.

20 the work, and also to provide an improved At the present time metal stock and other ma- 20 mounting and arrangement for the motor drive teri'als such as rods, tubes, bars and the like are for the wheel which will not interfere with the cut off by suitable saws or cutters, but these balance of the wheel support, and will facilitate devices are relatively slow, the saws need frequent operation of the device, re-sharpening and they cannot be used on cer- A further object is to provide an improved tain materials such as highly tempered steel and 25 means for mounting the wheel and its spindle so other materials. I have found, however, that by they may be assembled as a unit and applied and running a thin abrasive wheel at very high speeds removed as such from the machine. I can cut rapidly all of these various materials Another object is to provide an improved means and other materials such as tempered steels,

for cooperating with the wheel for removing dust special steel alloys and other materials which are 30 and particles of the wheel or work without the diflicult if not impossible to cut with the old cutnecessity for using a separate suction fan. ters, and can do it much more rapidly; easily and And still another object is to provide an imat less cost. I have found, however, that for the proved means for supporting the work with easy best operation the abrasive wheel must be run and quickly manipulated means for clamping the at a very high speed and that the work and the 35 work in position for the cut off operation and for wheel must be held very rigid and in given relathen releasing it. tion with a minimum of vibration during the out- With the foregoing and other objects in view, ting p at n as t w s or d s s ar v ry the invention consists in certain novel features of thin and compa v ly fra ile.

construction, combinations and arrangements of The improved construction illustrated has 40 a parts as will be more fully disclosed in connection P v n in Practice to be y fl tive ol this with the accompanying drawings. purpose due to the improved means for operating In thcse drawings; and mounting the cutting or abrasive disc and P Fig 1 is a from elevation of the machine the motor drive for it, the improved means for r 40 Fig 2 is a side elevation of the upper portion taking care of the dust and the abrasive particles, thereof; and an improved clamping or holding means for Fl 3 is a to Ian view; the work being Fig. 4 is a e ailed section substantially on This machine comprises bed 20 which may be line of Fig supported on any suitable means such as the legs 5 d fled b t 1 2|, and on this bed are mounted the upright 5' 1s sec Ion s an IV stands or brackets 22 carrying a heavy trunnion 0f 23 for pivotally supporting a, rigid swinging frame Fig. 6 1s a vertical longitudinal section through or bracket 24, hi frame or bracket has spaced the Spindle mounting for the wheel, the section bearings 25 on the trunnion 23 so 'as to give a very 55 being substantially on the line E6 of Fig, 8, and rigid, support for the frame, the bearing being spaced sumciently to give it rigid lateral support and insure that it is maintained in strict alignment and be required to move in a given plane as the cut off wheel carried thereby moves to and through the work. It is preferred that the bearings 25 be provided with means for a pressure grease feed to the bearing such as through the nipple 26 so as to provide a grease seal for'the entire bearing to protect the bearing against entrance of dirt and particularly abrasive particles from the cut off wheel. This grease seal is indicated at 21, Fig. 4, and although it will be obvious it is intended the bearing will be a good'running fit on the trunnion the clearances are exaggerated in the drawings to indicate the grease seal. As grease is forced into the bearing the old grease will be forced out and of course will carry with it dirt or abrasive particles and will keep the bearing clean so as to reduce wear and hold the swinging frame or bracket against lateral movement. In other words it will be held accurately in the proper position indefinitely.

At the free end of the swinging bracket or frame 24 is mounted, the cut oifwheel and its spindle. To facilitate mounting and demount ing, to assist in maintaining the spindle in proper alignment, and also to facilitate adjustment of the belt drive, this spindle with its bearings and the drive pulley are assembled as a unit outside I the machine and placed as such in its mountings mounted in the holder and secured therein by the caps 3| mounted by any suitable means such as the cap screws 32. These bearings are entirely enclosed and feltor other suitable material may be placed in the recesses 33 to prevent entrance of dirt or particles from the abrasive wheel. The

holder 28 has external eccentric bearings 34 which bearings are eccentric to the axis of the spindle 28. When mounting the spindle in the swinging frame 24 these eccentric bearings 34 are mounted in the split heads or supporting bearings 35 in the swinging frame and may be secured in any given position .by means-of the clamping screws 36.

The spindle 29 carries at one end the abrasive wheel or disc. l9 and it is preferably clamped on the spindle between the hubs or flanges 31 and 38. Flange 31 is keyed to the shaft and the disc. is flrmly clamped and held between the flanges by means of the nut 39. On the opposite end the spindle carries the grooved wheel or pulley 40 also keyed to the spindle and having any desired number of substantially V-shaped grooves for the V driving belts 41.. These belts run over a similar wheel or pulley 42 on the ar-- mature shaft 43 of an electric motor 44 which is controlled by any suitable switch and starting given position, and can be mounted by a permathe motor is in alignment with the axis of the trunnion 23 for mounting the swinging frame. 24, and therefore as the frame 24 is swung about the trunnion to move the cut off wheel toward or from the work the relation of the motor to the spindle'for the cut off wheel does not change. A special advantage of this arrangement is the permanent rigid mounting for the motor with reduced vibration to be transmitted to the cut all wheel, and also it permits the mounting of the motor entirely to one side or laterally of the plane of the cut off wheel so that particles removed from the, work or abrasive particles from the wheel are not carried back into the motor as they would likely be if the motor were directly in back of the wheel.

It will be evident that the tension of the belts 4| can be adjusted by turning the spindle assembly and moreparticularly the holder 28 in its bearing mounting 35 in the swinging frame 24. Thus the holder 28 may be provided with a radially extending socket 46 in which may be placed a bar by which after the clamping screws 36 are loosened, the holder 28 may be turned in the bearings 35, and as the bearings 34 are eccentric to the spindle 29 it will be evident that the turning of the holder 28 will shift the axis of the spindle toward and from the axis of the trunnion 23 and therefore the axis of the rotor shaft 43 of the motor. After adjustment it may be secured in its desired position by tightening the screws 36. Thus the tension of the driving belts may bequickly and easily adjusted without materially affecting the balance of the swinging frame 24 and without changing the position of the motor. These belts 4| may be protected and the operator also prevented from coming in contact with them by means of-any suitable guard .41 secured by any suitable means such as the brackets 48 and 49 to the frame 24.

The weight of the swinging bracket or frame 24 is counter-balanced by any suitable means,

that shown being a very effective one which can be kept entirely within the outlines of the machine and located under the bed wnere it is out of the way. Thus one .of the bearings 25 is provided with a downwardly extending boss 58 having a socket to receive an arm or bar 5|. At its lower end this bar has an eye 52 to which is sethe work during the operation of cutting it off.

In the present drawings the work is shown as a round bar 51; but of course, bars of various shapes and other articles maybe cutoff as desired. With this type of machine a good deal of the workto be performed is the cutting of bars or rods to given lengths, and it is therefore important in order to secure maximum production, that the work may be easily and quickly placed and clamped firmly in proper position,

and that the cut off piece be quickly removed so that the stock bar can be quickly shifted to its new, position for its next cut off operation. I have devised, a very simple and effective means for so holding the work which is illustrated more clearly in Figs. 9 and 10. This device comprises a base 58 which is secured to the bed 20 by any suitable means such as screws 59 passing through elongated slots 60 in the base to permit lateral adjustment of the base for proper alignment of the work holding means with respect to the cut 01! wheel. This base has on its upper surface guide ways 6| to receive work holding blocks 8! and 68. These blocks have on their lower edges longitudinal ribs 88 so they are guided for ad-. justment in the guide BI and may be secured in any adjusted position by the screws 85. The work such as the stock bar 81 is preferably fed from the left as viewed in. Fig. 1, that is. down-' wardly as viewed in Fig. 9 over the block 82, and this block has in its upper surface a recess to receive the bar, preferably a V-shaped recess 88 so as to be adapted to hold and center rods of different diameters. The block 68 supports the portion to be cut off, it being of course understood the cut off wheel passes through the bar through the gap 81 between the blocks 82 and 88. The work is clamped in position on these blocks by inverted V-shaped blocks 88 and 89 so mounted that they rest on the top of the bar and are carried by upright rods 10 bent upon themselves at their upper ends H and secured to the blocks 68 and 69 by any suitable means such as pins 12. These rods 10 are guided in upright bearings 18 forming part of the base 68 and are adjustably connected at their lower ends to a cross head 14. Also adjustably secured to this cross head is a rod connected to a foot operated lever or pedal 16, and a spring 18 connected to the bed and the cross head 14 tends to lift this head and associated parts and raise the clamping blocks 68 and 69 from the work. It will be evident that after the work bar 51 has been placed in proper position it may be easily and quickly clamped in this position and rigidly held therein by merely depressing the foot lever 16 which will clamp the block 68 and 69 down on top of the work and will clamp the work between these blocks 62 and 63.

As indicated above it is desirable that the cut off piece of the bar be removed as quickly as possible andthis is very important for increasing production. Therefore the block 68, which lies under and supports the piece being cut off, instead of having a v-shaped recess in its top surface is provided with an inclined wall 19. It will therefore be evident that with this construction as soon as the piece of the bar cut off is released by raising of the block 59 it will roll down the surface 19 out of the way as indicated by the dot and dash lines 80. Because of this inclined surface the V-shaped recess 8| on the under side of the clamping block 69 is of material assistance in holding the bar section 80 while it is being cut off. Any suitable stop may also be provided to limit feeding movements of the work bar 51 so that it is cut off to the proper length. Such a stop is indicated at 82 carried on a bar 88 adjustably mounted in suitable block 84 on the bed.

A slightly modified construction of work support and clamping means is shown in Figs. 11 and 12. Here the base 85 is similar to the base 58 and is mounted in the same manner; but instead of mounting both the rods 10 at the rear of the bar or the work 51 to be cut one of them indicated at 10a, is mounted at the front of this bar but otherwise the work is secured in the same manner.

In Figs. 15 and 16 is shown still another modified work holding and clamping means. In this construction the base 86 is pivoted at 81 to a plate 88 resting on the bed 20, and the clamping screws 59 pass through curved slots 89 concentric with the pivot 81. Also the upright clamping rods 10, guided as in the other forms through the bearings 88, pass through curved slots 8| in the plate 88. By this mounting the base 88 can the block 82 is cut off at its forward side 88 whilethe opposite block 94 is similarly cut off at 95. Therefore it will be evident the entire base 86 and the blocks carried thereby can be turned to the left or counter-clockwise to swing the work 81 to different angular relations with respect to the cut off wheel l8, and the walls 93-84 will permit the wheel to' clear the blocks as it passes through the work. The same kind of clamping blocks as indicated at 88 or 69 can be used on top'of the work but if both blocks 92 and 94 are formed with V-shaped recesses in which the work may rest then the down turned ends 10b of the rods will clamp the work in these recesses.

It is also important that a suitable guard be provided over the cut off wheel. I have found that this wheel, indicated at l9, can be made of a very thin disc of granular abrasive material such as carborundum or emery held together by a suitable binder. A very effective size has been found to be about of an inch thick and about 12 inches outside diameter although of course these sizes may be varied without departing from my invention. Of course such a wheel would be comparatively fragile and easily broken with lateral bending and it is therefore important that the work be very rigidly held during the cut off operation and also that the wheel be mounted on a rigid support which will permit minimum vibration and lateral movement so that. as the wheel moves to and through the work it will be held accurately in a given plane. This operation is effectively secured with the improved construction and arrangement above described.

The weel is operated at very high speeds and the higher the surface speed the better the operation inmost instances. It is preferably operated at a speed of at least 5,000 R. P. M. for a twelve inch wheel, which for this size of wheel means a surface speed of nearly 16,000 feet per minute. Even higher speeds are preferred and improved operation is secured thereby. Ten inch diameter wheels have been run at 8,500 R. P. M. which means a surface speed of about 22,000 feet per minute, and much higher speeds can be used. Somewhat lower speeds give fairly good results on certain materials but for satisfactory operation the wheels should be run at surface speeds of at least about 10,000 feet per minute, altho as indicated above the much higher speeds are preferred.

It has been found in practice that the wheels operated 15'. these high speeds last or wear much longer-and give more work per wheel than when operated at lowerspeeds. This is believed to be because for a given rate of feeding movement or much less bur on the work and therefore gives a finer cut.

I have also used abrasive wheels 14 and 16 inches in diameter with the revolutions per minute correspondingly determined to givethe surface speed desired. Of course these speeds may be varied, and the surface speed will be automatically reduced as the diameter of the wheel is reduced due to wear, but for best results the surface speed should be above 10,000 feet per minute and preferably 15,000 to 16,000 feet per minute or higher.

With these high speeds the wheels should be effectively guarded to prevent the operator coming in contact with it and also to prevent injuries from flying fragments should the wheel break in operation. To this end the wheel is enclosed in a guard extending over the top of the front and rear, and the opposite sides of the wheel. This guard extends down to the bed 20 on opposite sides of the wheel and is secured thereto as indicated at 01. The sides are provided with the aligned openings 88 to permit passage of the work to be cut, but it will be evident that the wheel is substantially entirely enclosed within this guard or casing. On the front side the casing may be open and closed by a removable cover 99 secured by any suitable means such as the thumb nuts I00 on bolts passing through notches IOI slot I03 above the spindle.

As the wheel I9 runs at a very high speed I have found that I can use this as a means for creating a draft for carrying away particles removed from the work as well as particles of abrasive material removed from the wheel. With the wheel rotating in the direction indicated by the arrow I06 in Fig. 7 it will be noted the lower portion of the wheel is moving toward the rear as indicated, and therefore there is an exit from the rear part of the guard casing air will be drawn inwardly through the openings 98 by the action of the wheel and forced outwardly through this rear passage. To facilitate this action the side walls of the guard casing at the rear edges of the openings 98 are flared outwardly and forwardly as indicated at I01 so as to catch the air and facilitate its entrance into the casing under the action of the wheel, and leading from the rear and lower part of the casing is an exit flue I 08 which may be led to any desired location. Preferably it discharges into a conduit I09 which may discharge into.any suitable receptacle such for example. as a tank holding water to receive and retain the particles carried downwardly by the flow of air. I have found that with this arrangement a strong flow of air is caused by rotation of thewheel which effectively carries on the dirt, chips and abrasive particles without the use of a separate fan or other auxiliary devices.

For swinging the wheel I9 toward and'from the work a suitable handle is connected to the swinging bracket or frame 24. In the present instance this handle comprises a. tubular rod I I0 adjustably secured to the forward end of the frame 24. Thus the frame may be provided with a socket III in which the handle extends and in which it is held by any suitable means such as a set screw II2. This permits adjustment of the handle to any position most convenient for operation by the operator, and as the swinging frame with the other elements carried thereby is effectively counterbalanced by the weight 50 the operator needs merely to overcome the friction of the various moving elements. The frame also preferably carries a stop rod Ill threaded in the frame for adjustment therein by any suitable means as the crank H4, and is adapted to engage a stop Hi to limit downward movement of the frame. The stop rod may be secured in adjusted position by the lock nut and lever I I5.

Having thus set forth the nature of my invention, what I claim is:

1. In a cut ofl machine of thecharacter described, a pivoted swinging frame, a cut oif'wheel carried by the frame to swing therewith, means for rotating the wheel at high speed, a guard extending over and on the opposite sides of said wheel and having openings at the 'lower part of and on opposite sides of said wheel for entrance of air to be carried rearwardly by the surface of the wheel, upright deflector at the rear edges of the openings and flared outwardly to direct air into the openings, and an exit flue leadingfrom the rear of the casing in alignment with the lower portion of the wheel to carry off the air forced rearwardly by the wheel together with solid particles from the wheel and work.

2. In a cut off machine of the character described, a frame, a cut off wheel carried by the frame, means for rotating the wheel at high speed, an enclosing guard casing extending over and on opposite sides of the wheel and open at the side of the wheel adjacent the work, the sides of the guard casing at opposite sides of the wheel being flared outwardly at the rear of said opening to facilitate entrance of air under action of the wheel, and an exit flue leading from the easing to the rear of the wheel.

3. In a cut on machine'of the character described, a bed, means on the bed for securing the work to be cut, a swinging frame hinged to the bed, a cut off wheel carried at the free end of the frame to swing toward and from'the work, a stationary guard casing enclosing the wheel and extending over the top and on the opposite sides thereof, one of said side walls having a slot for passage of the wheel support, and a cover slide-secured to the frame and movable therewith over said slot to keep the slot closedduring movement of the wheel toward and from the work.

4. In a cut off machine of thecharacter described, a bed, means on the bed for securing the work to be cut, a cut off wheel movable toward and from the work, said securing means comprising a V-block on one side of the wheel to support the work, a blockon the other side of the wheel having an inclined top wall so the cut off portion will automatically roll out of position, and manually operable clamps for resting on the top of the work to hold it in the blocks.

5. In a cut off machine of the character described, a bed, means on the bed for securing the work to be cut, a cut of]? wheel movable toward and from the work, said securing means comprising a recessed block on one side of the wheel, a block on the other side having an inclined top wallto permit the cut off work toroll automatically out of position, inverted V-shaped blocks to engage the top of the work over the first blocks, and means for shifting said upper blocks to and from the work.

6. In a cut off machine of the character described, a bed, means on the bed for securing the work to be cut, a cut off wheel movable toward and from the work, said securing means comprising a recessed block on one side of the wheel, a block on the other side having an inclined top wall to permit the cut ofl work to roll automatically out of position, inverted V-shaped blocks to engage the top of the work over the first blocks, upright rods extending through the bed and connected to the upper blocks, means tending to lift the latter blocks, and manually operated means for shifting the rods to clamp the blocks on to the work.

'7. In a out 0115 machine of the character described, a horizontal bed, means on the bed for securing the work to be cut, a cut ofi wheel movable toward and from the work, said securing means comprising a base mounted on the bed for turning movement about an upright axis and in a plane at right angles to the plane of the wheel,

.work holding means mounted on said base, means for securing the base in adjusted positions, clamps for extending over the work to hold it on the base, and manual means for operating said clamps up and down to release and clamp the work.

8. In a cut ofi machine of the character described, means for securing work to be cut, a out 01f wheel movable toward and from the work, said securing means comprising a support for the work, an upright rod extending from below the support to a point above it and then bent laterally and downwardly to provide a down turned end portion to rest on the work and clamp it, means for guiding said rod forup and down sliding movement in a straight line, and pedal operated means for operating said rod to clamp the work. I

. HARRY G. ROBINSON. 

